title: Antibody and immune memory persistence post infant hepatitis B vaccination.
abstract: OBJECTIVE
  This study aimed to evaluate the level of hepatitis B immunity among undergraduate students 23 years after commencement of the nationwide hepatitis B childhood immunization program in Malaysia.
  
  
  METHODS
  A total of 402 serum samples obtained from volunteer undergraduate students were screened for the presence of hepatitis B surface antibodies using qualitative ELISA.
  
  
  RESULTS
  Results showed that 62.7% of volunteers had protective anti-hepatitis B surface antigens (≥10 IU/L), of whom 67.9% received three doses of the vaccine. The estimated post-vaccination immunity was found to be at least 20 years, indicating persistent immunity against hepatitis B and a significant association (P < 0.05) with duration of vaccination. Anamnestic response 1 month post-hepatitis B booster was 94.0% and highly significant (P < 0.01). Isolated antihepatitis B core antigen (anti-HBc) prevalence was found to be 5.0%, all having had a positive anamnestic response.
  
  
  CONCLUSIONS
  Immunity after primary vaccination with hepatitis B recombinant vaccine persists for at least 20 years post-vaccination, with significant association with the number of vaccinations. Furthermore, the presence of anamnestic response to booster vaccine indicates long-lasting immunity despite decreasing antibody levels; therefore, the need for hepatitis B vaccine boosters may not be of significant benefit after complete infant vaccination.
authors.affiliation: Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia ; Department of Pathology and Medical Microbiology, College of Health Sciences, Usmanu Danfodiyo University Sokoto, Sokoto State, Nigeria.
authors.forename: Shuaibu A
authors.initials: SA
authors.lastname: Hudu
authors.forename: Yasmin A
authors.initials: YA
authors.lastname: Malik
authors.forename: Mohd Taib
authors.initials: MT
authors.lastname: Niazlin
authors.forename: Nabil S
authors.initials: NS
authors.lastname: Harmal
authors.forename: Ariza
authors.initials: A
authors.lastname: Adnan
authors.forename: Ahmed S
authors.initials: AS
authors.lastname: Alshrari
authors.forename: Zamberi
authors.initials: Z
authors.lastname: Sekawi
keywords: anamnestic response; booster vaccination; hepatitis B vaccination; persistent immunity